President Obama was schmoozing his way around the sports bar Gator’s Dockside, chatting up families and posing for photos as part of his campaign bus tour of Florida on Saturday night, when he stopped at a table of 10 people, including several children.

“He was born in Hawaii,” one woman said, pointing to a blond boy down the table.

The president lit up and flashed the Hawaiian shaka hand sign, which the boy — Andre Wupperman, who will be 7 next week — returned.

“You were born in Hawaii?” Mr. Obama asked, then broke out into a smile. “You have a birth certificate?”